"Real" assessments

Here in Florida we have begun FCAT, which mean two weeks of intensive criterion referenced and norm-referenced assessment at grades 3-11. As I watch the students focus all their energies on FCAT, I am struck by how the level of effort applied on these assessments differs from that applied on other assessments, including Think Link. While many of our students are determined to show how well they can perform on all assessments, there are also those who only give their all when they feel the stakes are high, as they certainly are for FCAT. Any thoughts on how we can encourage a more consistent performance from our students?